POS0022 CHARACTERISTICS OF PAIN IN UK PATIENTS WITH BEHÇET’S SYNDROME: A PROSPECTIVE OBSERVATIONAL COHORT STUDY
Authors: K. Plant, L. Chadwick, A. Goebel, J. Nair, R. Moots, N. Goodson
Journal: Annals of the Rheumatic Diseases (2022)

<h3>Background</h3> Behçet's syndrome (BS) is a rare multi-organ systemic vasculitis of unknown aetiology with hallmark manifestations of mucocutaneous ulcers and skin lesions. Morbidity is high in BS; with high prevalence of pain, fatigue and poor quality of life. Fibromyalgia syndrome (FMS), a common cause of widespread musculoskeletal (MSK) pain, is more prevalent in rheumatological conditions including BS. However, there is limited research into the aetiology and characteristics of pain in BS. To our knowledge, there are no studies describing pain in a UK BS population. <h3>Objectives</h3> To describe the pain characteristics and incidence of comorbid FMS in patients with BS, and investigate their relationship with disease activity. <h3>Methods</h3> This is a prospective observational study of patients with a diagnosis of BS attending the National Centre for BS in Liverpool between February 2017 and March 2019. Patients were defined as "Complete BS" if they satisfised the International Study Group criteria and "Incomplete BS" if they met one criterion plus genital ulcers. BS severity was assessed using the Behçet's disease current activity form (BDCAF). High and low disease activity were defined as a BDCAF score ≥ 4 or &lt; 4 respectively. FMS prevalence was determined from consultant diagnosis. To minimise inflation of disease severity in the FMS cohort, a modified BDCAF (with arthralgia and arthritis components removed) was calculated (mBDCAF). Assessments of pain included: The Pain Visual Analogue Scale (VAS), Pain Mannequin and Short Form McGill (SF-MPQ-2) questionnaires. Generalised pain data was imputed from the pain mannequin using the American College of Rheumatology 2016 definition, pain in all quadrants (upper left, upper right, lower left and lower right) plus axial distribution. Pain and FMS prevalence were compared between high and low disease activity using Chi-Square Test of Independence. The mean mBDCAF was compared between those with and without FMS using a student's T-Test. Data analysis was conducted in Microsoft Excel and STATA. <h3>Results</h3> 101 patients, 75 female and 26 male, of age 10-74 years were assessed. 81.2% of patients met the ISG criteria (Complete BS); The remaining 18.8% met Incomplete BS status. 90% of patients reported moderate-severe pain with a median VAS score of 68/100 [38, 81]. 35.6% of patients had a diagnosis of FMS and 46.5% experience generalized pain. 76% of patients with high disease activity reported severe pain, a VAS greater than 70, compared to 39.1% with low disease activity <i>(p=.003).</i> Pain was more generalised in high disease activity (72%) compared to low disease activity (37.7%) <i>(p=.003).</i> The qualitative assessment of pain (SF-MPQ-2) stratified by disease activity, Figure 1, demonstrates that pain intensity is higher in high disease activity. Continuous descriptive terms were most commonly selected indicating a chronic nature of the pain. Concomitant FMS diagnosis was more prevalent in the high disease activity group (52%) than the low disease activity group (29%) <i>(p=0.04).</i> The mean mBDCAF of patients with FMS was 2.09 ± 1.3 compared to 1.53 ± 1.3 in patients without FMS <i>(p= 0.047).</i> <h3>Conclusion</h3> This the first study to describe the pain experience of a UK population of BS patients. The majority of patients experience moderate to severe chronic MSK pain. Severe generalised MSK pain is more prevalent in those with high BS disease activity. We have demonstrated a relationship between high disease activity, worse pain intensity, and comorbid FMS. Our findings pose new questions into the research of pain in BS. Further studies are required to explore the mechanism of generalised pain and its correlation with disease activity. <h3>Disclosure of Interests</h3> None declared